Final authorization would allow the airlines to combine their networks and complete a commercial relationship driven by Delta’s recent purchase of a 49 percent stake in Virgin, the U.S. Department of Transportation said today in a filing. Anthony Black, a spokesman for Delta, confirmed the filing.

The carriers have a code-share agreement enabling bookings to be made on each other’s jets on one itinerary, and antitrust immunity would deepen the ties with steps such as sharing costs as though they were a single entity. U.S. and European laws ban foreign majority ownership of airlines.

Delta, based in Atlanta, bought the stake in Virgin from Singapore Airlines Ltd. for $360 million this year to add trans- Atlantic flights, the world’s richest market for premium passengers. The move is a challenge to British Airways and AMR Corp.’s American Airlines, which now control more than half of that service.

Editors: Ed Dufner and John Lear.

To contact the reporter on this story: Mary Jane Credeur in Atlanta at mcredeur@bloomberg.net. To contact the editor responsible for this story: Ed Dufner at edufner@bloomberg.net.

The Skift Daily newsletter puts you ahead of everyone about the future of travel. Subscribe now.